The present invention is concerned with adhesives in general and to adhering a plurality of substrates.
It is well known in the art today that significant difficulties are associated with securing the side body moldings to vehicles due to the method of adhering the moldings to the vehicles. Currently employed is a polyvinyl chloride molding. The industry has applied a plurality of hot melt adhesive beads on the outer periphery of said molding with a bead of one component moisture curable urethane adhesive in between the two hot melt adhesives. The basic purpose of said technique is to have an immediate adhesion as the hot melt adhesive cools while a more permanent bond is effected as the one component urethane adhesive cures. However, it has been found through experience that the adhesive system employed is not fully satisfactory. Also, if a pressure sensitive adhesive is used, the molding comes away from the body of the vehicle due to degradation of the adhesive and its adhering ability to the substrate by virtue of a delamination principle or by virtue of the plasticizer that may be present in the paint on the substrate or the plasticizer that may be present in the polyvinyl chloride molding itself. Also, it has been found that the adhesion of the moldings to top coat paints of the non aqueous dispersion type is very poor. Additionally, the transportation industry has been looking for a variety of means for decreasing the weight of automotive vehicles as well as to save energy in the fabrication of vehicles. The weight problem can be partially solved by using chemical adhesives to secure a variety of components used in the transportation industry, thereby eliminating mechanical attachments or fasteners that may be employed. Additionally, mechanical supports that are used to hold windows in place may likewise be supplanted with the use of an adhesive system. Deck lids and hoods which require mechanical fastening techniques or costly supplementary aids, such as welding, can also be a place for the use of adhesives, thereby decreasing the weight of the mechanical components. Deck lids and hoods which require dual methods to insure precise fit involve costly welding and unsatisfactory adhesive bonding which result in high labor intensity due to clean up of equipment and parts and the buffing and polishing of parts to eliminate pinch weld marks. These are other advantages for adhesive use.
The theory of adhesives and the use of various adhesives are generally well known in the art. For a background on adhesives, see the Handbook of Adhesive Bonding edited by Charles V. Eagle, published by McGraw Hill, Inc., in particular, Chapter 19. See also Applied Polymer Science edited by J. Kenneth Craver and Roy W. Tess, published by the American Chemical Society, 1975, pages 473 and following, for a recitation of well known adhesives, hereby incorporated by reference.